    //兼容  
    window.URL = window.URL || window.webkitURL;
    navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia ||
        navigator.msGetUserMedia;

    var HZRecorder = function (stream, config){
        let audioContext;
        config = config || {};
        config.sampleBits = config.sampleBits || 8; //采样数位 8, 16  
        config.sampleRate = config.sampleRate || (44100 / 6); //采样率(1/6 44100)  


        //创建一个音频环境对象  
        audioContext = window.AudioContext || window.webkitAudioContext;
        var context = new audioContext();

        //将声音输入这个对像  
        var audioInput = context.createMediaStreamSource(stream);

        //设置音量节点  
        var volume = context.createGain();
        audioInput.connect(volume);

        //创建缓存，用来缓存声音  
        var bufferSize = 4096;

        // 创建声音的缓存节点，createScriptProcessor方法的  
        // 第二个和第三个参数指的是输入和输出都是双声道。  
        var recorder = context.createScriptProcessor(bufferSize, 2, 2);

        var audioData = {
            size: 0 //录音文件长度  
                ,
            buffer: [] //录音缓存  
                ,
            inputSampleRate: context.sampleRate //输入采样率  
                ,
            inputSampleBits: 16 //输入采样数位 8, 16  
                ,
            outputSampleRate: config.sampleRate //输出采样率  
                ,
            oututSampleBits: config.sampleBits //输出采样数位 8, 16  
                ,
            input: function (data) {
                this.buffer.push(new Float32Array(data));
                this.size += data.length;
            },
            compress: function () { //合并压缩  
                //合并  
                var data = new Float32Array(this.size);
                var offset = 0;
                for (var i = 0; i < this.buffer.length; i++) {
                    data.set(this.buffer[i], offset);
                    offset += this.buffer[i].length;
                }
                //压缩  
                var compression = parseInt(this.inputSampleRate / this.outputSampleRate);
                var length = data.length / compression;
                var result = new Float32Array(length);
                var index = 0,
                    j = 0;
                while (index < length) {
                    result[index] = data[j];
                    j += compression;
                    index++;
                }
                return result;
            },
            encodeWAV: function () {
                var sampleRate = Math.min(this.inputSampleRate, this.outputSampleRate);
                var sampleBits = Math.min(this.inputSampleBits, this.oututSampleBits);
                var bytes = this.compress();
                var dataLength = bytes.length * (sampleBits / 8);
                var buffer = new ArrayBuffer(44 + dataLength);
                var data = new DataView(buffer);

                var channelCount = 1; //单声道  
                var offset = 0;

                var writeString = function (str) {
                    for (var i = 0; i < str.length; i++) {
                        data.setUint8(offset + i, str.charCodeAt(i));
                    }
                };

                // 资源交换文件标识符   
                writeString('RIFF');
                offset += 4;
                // 下个地址开始到文件尾总字节数,即文件大小-8   
                data.setUint32(offset, 36 + dataLength, true);
                offset += 4;
                // WAV文件标志  
                writeString('WAVE');
                offset += 4;
                // 波形格式标志   
                writeString('fmt ');
                offset += 4;
                // 过滤字节,一般为 0x10 = 16   
                data.setUint32(offset, 16, true);
                offset += 4;
                // 格式类别 (PCM形式采样数据)   
                data.setUint16(offset, 1, true);
                offset += 2;
                // 通道数   
                data.setUint16(offset, channelCount, true);
                offset += 2;
                // 采样率,每秒样本数,表示每个通道的播放速度   
                data.setUint32(offset, sampleRate, true);
                offset += 4;
                // 波形数据传输率 (每秒平均字节数) 单声道×每秒数据位数×每样本数据位/8   
                data.setUint32(offset, channelCount * sampleRate * (sampleBits / 8), true);
                offset += 4;
                // 快数据调整数 采样一次占用字节数 单声道×每样本的数据位数/8   
                data.setUint16(offset, channelCount * (sampleBits / 8), true);
                offset += 2;
                // 每样本数据位数   
                data.setUint16(offset, sampleBits, true);
                offset += 2;
                // 数据标识符   
                writeString('data');
                offset += 4;
                // 采样数据总数,即数据总大小-44   
                data.setUint32(offset, dataLength, true);
                offset += 4;
                // 写入采样数据   
                if (sampleBits === 8) {
                    for (var i = 0; i < bytes.length; i++, offset++) {
                        var s = Math.max(-1, Math.min(1, bytes[i]));
                        var val = s < 0 ? s * 0x8000 : s * 0x7FFF;
                        val = parseInt(255 / (65535 / (val + 32768)));
                        data.setInt8(offset, val, true);
                    }
                } else {
                    for (var i = 0; i < bytes.length; i++, offset += 2) {
                        var s = Math.max(-1, Math.min(1, bytes[i]));
                        data.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
                    }
                }

                return new Blob([data], {
                    type: 'audio/wav'
                });
            }
        };

        //开始录音  
        this.start = function () {
            audioInput.connect(recorder);
            recorder.connect(context.destination);
        };

        //停止  
        this.stop = function () {
            recorder.disconnect();
        };

        //获取音频文件  
        this.getBlob = function () {
            this.stop();
            return audioData.encodeWAV();
        };

        //回放  
        this.play = function (audio) {
            audio.src = window.URL.createObjectURL(this.getBlob());
        };

        //上传  
        this.upload = function (url, callback) {
            var fd = new FormData();
            fd.append('audioData', this.getBlob());
            var xhr = new XMLHttpRequest();
            if (callback) {
                xhr.upload.addEventListener('progress', function (e) {
                    callback('uploading', e);
                }, false);
                xhr.addEventListener('load', function (e) {
                    callback('ok', e);
                }, false);
                xhr.addEventListener('error', function (e) {
                    callback('error', e);
                }, false);
                xhr.addEventListener('abort', function (e) {
                    callback('cancel', e);
                }, false);
            }
            xhr.open('POST', url);
            xhr.send(fd);
        };

        //音频采集  
        recorder.onaudioprocess = function (e) {
            audioData.input(e.inputBuffer.getChannelData(0));
            //record(e.inputBuffer.getChannelData(0));  
        };

    };
    //抛出异常  
    HZRecorder.throwError = function (message) {
        throw new function () {
            this.toString = function () {
                return message;
            };
        };
    };
    //是否支持录音  
    HZRecorder.canRecording = (navigator.getUserMedia != null);
    //获取录音机  
    HZRecorder.get = function (callback, config) {
        if (callback) {
            if (navigator.getUserMedia) {
                navigator.getUserMedia({
                        audio: true
                    } //只启用音频  
                    ,
                    function (stream) {
                        var rec = new HZRecorder(stream, config);
                        callback(rec);
                    },
                    function (error) {
                        switch (error.code || error.name) {
                            case 'PERMISSION_DENIED':
                            case 'PermissionDeniedError':
                                HZRecorder.throwError('用户拒绝提供信息。');
                                break;
                            case 'NOT_SUPPORTED_ERROR':
                            case 'NotSupportedError':
                                HZRecorder.throwError(
                                    '<a href="http://www.it165.net/edu/ewl/" target="_blank" class="keylink">浏览器</a>不支持硬件设备。'
                                );
                                break;
                            case 'MANDATORY_UNSATISFIED_ERROR':
                            case 'MandatoryUnsatisfiedError':
                                HZRecorder.throwError('无法发现指定的硬件设备。');
                                break;
                            default:
                                HZRecorder.throwError('无法打开麦克风。异常信息:' + (error.code || error.name));
                                break;
                        }
                    });
            } else {
                HZRecorder.throwErr(
                    '当前<a href="http://www.it165.net/edu/ewl/" target="_blank" class="keylink">浏览器</a>不支持录音功能。'
                );
                return;
            }
        }
    };

export default HZRecorder;

